The DiaSource Calcitonin-U.S. IRMA is an immunoradiometric assay based on coated tube separation.
It uses monoclonal antibodies directed against distinct epitopes of human Calcitonin. The capture antibody is attached to the lower inner surface of a plastic tube. Calibrators and samples are dispensed into the tubes and bind to the capture antibody. The signal antibody (radiolabelled) is added immediately and after an incubation which allows the immunologic reaction, the tubes are emptied and washed to remove the excess unbound antibody.
The radioactivity bound to the tubes is directly proportional to the initial antigen concentration in the calibrators and samples.